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Within the British nuclear inventory, waste is classified into three main categories, including Intermediate Level Waste (ILW). ILW mainly consists of fuel casing metallic swarf, where parts of uranium metal are also expected to have been agglomerated. ILW treatment route includes the material storage in stainless steel drums and subsequent grout encapsulation. The solidified matrix is believed to maintain the radioactive waste fully confined and immobile. Recent inspections revealed mechanical distortion around the steel liner in a proportion of the inspected drums. The distortion has been ascribed to the corrosion of the encapsulated metallic parts. The generated corrosion products occupy greater volume than the parent metal, resulting in an internal volume expansion which imposes stress/strain on the encapsulants. This study attempts to correlate the level of internal corrosion with the magnitude of package degradation in ILW drum–simulant systems by favouring the use of powerful synchrotron X-rays.

Here we report the results of multiple analytical techniques on sub-mm particulate material derived from Unit 1 of the Fukushima Daiichi Nuclear Power Plant to provide a better understanding of the events that occurred and the environmental legacy. Through combined x-ray fluorescence and absorption contrast micro-focused x-ray tomography, entrapped U particulate are observed to exist around the exterior circumference of the highly porous Si-based particle. Further synchrotron radiation analysis of a number of these entrapped particles shows them to exist as UO2—identical to reactor fuel, with confirmation of their nuclear origin shown via mass spectrometry analysis. While unlikely to represent an environmental or health hazard, such assertions would likely change should break-up of the Si-containing bulk particle occur. However, more important to the long-term decommissioning of the reactors at the FDNPP (and environmental clean-upon), is the knowledge that core integrity of reactor Unit 1 was compromised with nuclear material existing outside of the reactors primary containment., The larger particulates from reactor Unit 1 of the Fukushima Daiichi Nuclear Power Plant have received sparse attention compared to the Unit 2 particulate. Here the authors perform the higher-resolution and 3-dimentional analysis of several high-density micron-scale fragments, from within a larger Unit 1-derived representative ejecta particle.

The study explores carbon quantum dots (C-dots) as potential candidates for enhancing the signal sensitivity of an electrochemical sensor devised for biologically important molecule, such as uric acid (UA). The C-dots were evaluated for their electrochemical characteristics in combination with Fe3O4 nanoparticles (Fe3O4 NPs), which were applied as the primary electro-catalytic promoter. The hybrid nanocomposite (C-dots/Fe3O4 HCs) formation was achieved by facilitating the adsorption of C-dots over Fe3O4 NPs using amine-carbonyl interactions. Unlike, one pot method, the proposed strategy enables aggregation-free coverage of Fe3O4 NPs with highly conductive layer of C-dots that can act as conduction centres to support ultra-fast electron transfer kinetics to satisfy the need of high signal sensitivity. The hybrid composite demonstrated remarkable signal improvement when tested against the electrochemical oxidation of UA. The heighten current response and lower over-potential values enabled development of a DC-amperometric (DC-AMP) sensor for UA with a linear working range of 0.01 to 0.145 μM and signal sensitivity measurable up to 6.0 × 10−9 M. The said improvement was manifested as a synergetic outcome of active redox couple (Fe (III/II)), larger surface area of Fe3O4 NPs engulfed with a layer of highly conductive C-dots acting as efficient charge sensitisers.

The reaction of unirradiated-U with liquid water was investigated under initial vacuum-contained conditions. Ten samples were examined at varying temperatures and reaction times. Post-corrosion examination of the surfaces was conducted using FIB, SIMS and XRD. Measurements of the reacting water pH and degassing of the samples was conducted after the reaction was stopped. From the analyses, it was concluded that bulk-UH 3 formation occurred on the majority of the samples. It is suggested that UH 3 formation was facilitated by a critical ‘threshold’ headspace pressure ∼0.5bar over which pressure deficiency is observed in the free headspace.

Decommissioning of the damaged Chernobyl nuclear reactor Unit 4 is a top priority for the global community. Before such operations begin, it is crucial to understand the behaviour of the hazardous materials formed during the accident. Since those materials formed under extreme and mostly unquantified conditions, modelling alone is insufficient to accurately predict their physical, chemical and, predominantly, mechanical behaviour. Meanwhile, knowledge of the mechanical characteristics of those materials, such as their strength, is a priority before robotic systems are employed for retrieval and the force expected from them to be exerted is one of the key design questions. In this paper we target to measurement of the standard mechanical properties of the materials formed during the accident by testing small-scale, low radioactivity simulants. A combined methodology using Hertzian indentation, synchrotron X-ray tomography and digital volume correlation (DVC), was adopted to estimate the mechanical properties. Displacement fields around the Hertzian indentation, performed in-situ in a synchrotron, were measured by analysing tomograms with DVC. The load applied during the indentation, combined with full-field displacement measured by DVC was used to estimate the mechanical properties, such as Young's modulus and Poisson's ratio of these hazardous materials.

s: Background: Aseptic loosening of total joint replacements (TJRs) continues to be the main cause of implant failures. The socioeconomic impact of surgical revisions is hugely significant; in the United Kingdom alone, it is estimated that £137 m is spent annually on revision arthroplasties. Enhancing the longevity of titanium implants will help reduce the incidence and overall cost of failed devices. Methods: In realising the development of a superior titanium technology, we exploited the natural affinity of titanium for phosphonic acids and developed a facile means of coating the metal with (3S)1-fluoro-3-hydroxy-4-(oleoyloxy)butyl-1-phosphonate (FHBP), a phosphatase-resistant analogue of lysophosphatidic acid (LPA). Importantly LPA and selected LPA analogues like FHBP synergistically cooperate with calcitriol to promote human osteoblast formation and maturation. Results: Herein, we provide evidence that simply immersing titanium in aqueous solutions of FHBP afforded a surface that was superior to unmodified metal at enhancing osteoblast maturation. Importantly, FHBP-functionalised titanium remained stable to 2 years of ambient storage, resisted ∼35 kGy of gamma irradiation and survived implantation into a bone substitute (Sawbone™) and irrigation. Conclusion: The facile step we have taken to modify titanium and the robustness of the final surface finish are appealing properties that are likely to attract the attention of implant manufacturers in the future. The translational potential of this article: We have generated a functionalised titanium (Ti) surface by simply immersing Ti in aqueous solutions of a bioactive lipid. As a facile procedure it will have greater appeal to implant manufacturers compared to onerous and costly developmental processes.

The appraisal is strongly focussed on challenges associated with the nuclear sector, however these are representative of what is generally encountered by a range of engineering applications. Ensuring structural integrity of key nuclear plant components is essential for both safe and economic operation. Structural integrity assessments require knowledge of the mechanical and physical properties of materials, together with an understanding of mechanisms that can limit the overall operating life. With improved mechanistic understanding comes the ability to develop predictive models of the service life of components. Such models often require parameters which can be provided only by characterisation of processes occurring in situ over a range of scales, with the sub-micrometre-scale being particularly important, but also challenging. This appraisal reviews the techniques currently available to characterise microstructural features at the nanometre to micrometre length-scale that can be used to elucidate mechanisms that lead to the early stages of environmentally-assisted crack formation and subsequent growth. Following an appraisal of the techniques and their application, there is a short discussion and consideration for future opportunities., Measurement techniques; environmentally assisted cracking; steel; length scale; nuclear reactor; Materials Characterization; Nuclear Engineering; Materials Science; Materials Property; Corrosion; Materials Structure

In the UK, the typical route being followed to handle metallic Intermediate Level Waste (ILW) derived from decladding of irradiated nuclear fuel is to primarily deposit it within stainless steel drums/boxes and subsequently encapsulate it into grout. Thus, a monolithic bond between the waste and the encapsulants can be achieved. However, recent inspections have revealed bulges around the circumference in a considerable proportion of the inspected packages. This distortion has been ascribed to the interior metallic corrosion–induced volume expansion, occurring throughout the waste packages storage period. Throughout this period, the volume expansion taking place in the core of the ILW drums has imposed continuously growing levels of strain on the surrounding encapsulants, i.e. grout and steel confinement. As a result, the encapsulants may exhibit considerable damage, in the form of cracks in the grout or/and steel distortion, threatening the integrity of the packages and, consequently, raising safety concerns within the nuclear community. Herein, experimental work performed on ILW drum–simulant packages is described, attempting to evaluate the performance of the packages under an internal corrosion–induced volume expansion.

This study explores the potential of a newly-developed indium tin oxide (ITO) based electrode for the development of an electro-catalytic inhibition sensor system for organophosphorus pesticides. The sensor relies on the redox signal inhibition of pralidoxime chloride (PAM) immobilised over the pimelic acid functionalised CuO nanostructures grown in-situ over an ITO substrate. The in-situ growth enabled on-pot modification and functionalisation of ITO electrodes with the formation of uniform nanostructures possessing high surface area and excellent interface contact. The versatility of the proposed electrode was evident from its excellent electrochemical characteristics evaluated in comparison to bare and slurry-driven glassy carbon electrodes (GCEs). The high structural uniformity and greater surface coverage achieved by in-situ growth provided a uniform surface environment for electrode-analyte interaction, leading to good inhibition signal sensitivity and repeatability. The developed sensor was successful in detecting chlorpyrifos, fenthion and methyl parathion within the concentration range of 0.01–0.16 μM with signal sensitivity reaching down to 1.6 × 10−9, 2.5 × 10−9 and 6.7 × 10−9 M respectively. Moreover, the proposed sensor demonstrated excellent applicability when tested for chlorpyrifos from vegetable extracts using a standard addition method.

This study describes the hydrothermal synthesis of NiO, CuO and Co3O4 nanostructures using acetylsalicylic acid (ASA) as a growth-controlling/directing agent. The as-synthesised nanostructures were shown to possess unique structural features and distinct morphologies, portraying the efficiency of ASA as a suitable growth modifier. The formed metal oxide nanostructures, when used for electrode modification purposes, exhibited excellent electro-catalytic capabilities against the oxidation of nelbuphine hydrochloride (NAL) in aqueous buffer solution. The modified electrodes exhibited distinct electrochemical characteristics, with CuO-based electrodes exhibiting a superior signal sensitivity and lower over-potential value compared to the NiO and Co3O4 nanostructures. The study further explores the variation in the observed electro-catalytic oxidation signal referenced to the distinct morphologies of the metal oxides nanostructures. The CuO-based electrode was selected for the sensitive quantification of NAL in aqueous solution over the linear range 0.001–2.25 μM. The electrode demonstrated excellent working linearity, with signal sensitivity achieved down to 1 × 10− 4 μM. Moreover, the successful quantification of NAL in complex matrices, such as human urine and clinical waste water, further reflected the analytical capability of the proposed sensor.

To accurately predict the initiation and evolution of uranium hydride potentially present in nuclear waste containers, studies of simulated conditions are required. Here, for the first time, the uranium-deuterium reaction was examined in-situ, in real time, whilst within grouted media. A deuterium gas control rig and stainless steel-quartz glass reaction cell were configured on a synchrotron beam line to collect X-ray diffraction and X-ray tomography data. It was found that deuteride formation was limited by the uranium and grout thermal conductivities and deuteride initiation only commenced above a threshold temperature. Strong adherence between uranium oxide and grout was also observed.

Commercial graphites are used for a wide range of applications. For example, Gilsocarbon graphite is used within the reactor core of Advanced Gas Cooled Reactors (UK) as a moderator. In service, the mechanical properties of the graphite are changed as a result of neutron irradiation induced defects and porosity arising from radiolytic oxidation. In this paper, we discuss measurements undertaken of mechanical properties at the micro-length-scale for virgin and irradiated material. These data provide the necessary inputs to an experimentally-informed model that predicts the deformation and fracture properties of Gilsocarbon graphite at the centimetrelength-scale. The results provide an improved understanding of how the mechanical properties and fracture characteristics of this type of graphite change as a result of exposure to the service environment.

Both the three-dimensional internal structure and elemental distribution of near-field radioactive fallout particulate material released during the March 2011 accident at the Fukushima Daiichi Nuclear Power Plant is analysed using combined high-resolution laboratory and synchrotron radiation x-ray techniques. Results from this study allow for the proposition of the likely formation mechanism of the particles, as well as the potential risks associated with their existence in the environment, and the likely implications for future planned reactor decommissioning. A suite of particles is analyzed from a locality 2 km from the north-western perimeter of the site – north of the primary contaminant plume in an area formerly attributed to being contaminated by fallout from reactor Unit 1. The particles are shown to exhibit significant structural similarities; being amorphous with a textured exterior, and containing inclusions of contrasting compositions, as well as an extensive internal void volume – bimodal in its size distribution. A heterogeneous distribution of the various elemental constituents is observed inside a representative particle, which also exhibited a Fukushima-derived radiocesium (134Cs, 135Cs and 137Cs) signature with negligible natural Cs. We consider the structure and composition of the particle to suggest it formed from materials associated with the reactor Unit 1 building explosion, with debris fragments embedded into the particles surface. Such a high void ratio, comparable to geological pumice, suggests such material formed during a rapid depressurisation and is potentially susceptible to fragmentation through attrition.

Synthetic polygranular graphites of various grades and manufacturing routes are used in nuclear reactors for power generation, and may be used in potential fourth generation and other advanced reactor designs that will operate at higher temperature. Attention is given in this paper to isostatically-moulded synthetic polygranular graphites with porosities in the range 8% to 18%. The lattice parameters a and c for the hexagonal graphite have been measured over the temperature range from room temperature to 800°C by x-ray diffraction. The variation with temperature of the crystal lattice parameters, coherence length (crystallite size) and microstrain are discussed with reference to the microstructure and the relative strength of the bonds in-plane and normal to the graphene layers.

MXene-based hybrid composites are gaining substantial attention due to their impressive chemical and electronic characteristics. Herein, an in-situ engineered heterojunction is constructed using partially-oxidised Ti3C2Tx sheets and photo-active NiWO4 nanoparticles (NPs). The NiWO4 NPs were used to induce partial surface oxidation of Ti3C2Tx, resulting in the formation of a Ti3C2Tx-TiO2/NiWO4 hybrid composite (MX-NiWO4). The electrocatalytic and photo-electrochemical (PEC) characteristics of MX-NiWO4 were studied in reference to the reduced graphene oxide-NiWO4 (rGO-NiWO4) and H2O2-treated Ti3C2Tx (MX-H2O2) hybrids. The MX-NiWO4, based on its in-situ driven configuration, constructed an ideal interfacial arrangement for the electrocatalytic mechanism-based PEC immuno-sensing of prostate-specific antigens (PSA). The developed PEC biosensor was capable of detecting PSA, over a wide detection range of 1.2 fg.mL−1 to 0.18 mg.mL−1, with a detection limit of 0.15 fg.mL-1. The synergic integration of Ti3C2Tx with photo-active NiWO4 offers a superior signal response and practical applicability when used for the quantification of PSA from human saliva samples, anticipating the hybrid’s promising future in clinical detection.

This work describes the fabrication of unique arrow head shaped CuO nanostructures using simple hydrothermal treatment method. The highly attractive features were obtained by the application of glutaric acid utilised simultaneous as template and functionalising agent. The functionalised nanostructures were known to possess excellent potential towards the electro-catalytic oxidation of carbofuran pesticide. The generated intense electrochemical signal with lower potential value enabled sensitive and selective determination of carbofuran up to 1×10−3 µM with wide sensing window in range of 0.01 to 0.16 µM. The feasibility of the developed sensor system for the practical application was also studied by testing its potential in real sample extracts of various vegetables. The excellent recoveries demonstrated the analytical robustness of the developed sensor system. The sensor system utilises a new and simple approach towards sensitive determination of toxic pesticides reflecting its wide spectrum application in various fields.

Nuclear graphite has a complex microstructure and displays quasi-brittle fracture characteristics. Multi-scale experimental characterisation (micrometre-scale to centimetre-scale) and numerical modelling were performed for (i) PG25 filter graphite with pores only (52 vol.%); and (ii) Gilsocarbon nuclear graphite with pores and aggregates. Modelling results show that the average mechanical properties and the scatter of the data both decrease monotonically with increase in specimen size. Strain fields and crack patterns were modelled and fit with experimental observations. The benefits of the model as a valuable tool in studying the influence of microstructural parameters on the fracture of nuclear graphites are discussed.

This work reports a highly sensitive electrochemical sensor for organophosphate pesticide (malathion) based on unique and attractive CuO nanostructures. The discussed nanostructures were synthesize ...

During the early years of nuclear industry within the UK, the typical route followed to handle Magnox (Mg-Al alloy) casing after separation from the nuclear fuel has been immersion in water temporarily in specifically-designed water ponds. Over the decades of storage, Magnox has been corroding in water, resulting in the formation of sludge within the ponds; known as Corroded Magnox Sludge. Uranium, which has been also contained within the ponds as a result of faults occurring during fuel-casing separation, is susceptible to corrosion in water-rich environments. Under certain circumstances, uranium corrosion products can be highly pyrophoric during oxidation in air. This raises serious concerns regarding the safety margins of nuclear pond decommissioning. The present study attempts to shed light on the behaviour of uranium in a Magnox sludge-surrogate environment, using X-ray computed tomography at distinct time intervals over an 18-month period. Focus was given onto the uranium-sludge interface to determine metallic corrosion onset and evolution.

WOS: 000486132800032, PubMed: 31233985, This study describes the construction of highly-sensitive photo-electrochemical (PEC) immunosensor for the detection of neuron-specific enolase (NSE). The biosensing platform is comprised of photo-active NiWO4 nanostructures, in-situ-grown over a conductive substrate (indium tin oxide) using a low-temperature template-based co-precipitation approach. The discussed approach enables the formation of discrete, yet morphologically-analogous, nanostructures with complete coverage (pinhole-free) of the electrode surface. The in-situ-grown nanostructure possess dense population with sharp saw-blade like morphological features that can support substantial immobilisation of anti-NSE agent. The constructed platform demonstrated excellent photo-catalytic activity towards uric acid (UA) which served as the base for the Electrochemical -mechanism (EC) based PEC inhibition sensing. The detection of NSE, relied on its obstruction in analytical signal observed for the photo-oxidation of UA after binding to the electrode surface via protein-antibody interaction. The constructed PEC immunosensor exhibits signal sensitivity up to 0.12 ng mL(-1) of NSE with excellent signal reproducibility and electrode replicability. Moreover, the constructed platform was successfully used for NSE determination in human serum samples.

The clean-up effort that is occurring across the region affected by the 2011 Fukushima Daiichi Nuclear Power Plant accident is unprecedented in its magnitude as well as the financial cost that will eventually result. A major component of this remediation is the stripping of large volumes of material from the land surface, depositing this into large waste storage bags before placing these 1 cubic meter bags into specially constructed stores across Fukushima Prefecture. In this work, using an unmanned aerial vehicle to perform radiological surveys of a site, the time-resolved distribution of contamination during the construction of one of these waste storage sites was assessed. The results indicated that radioactive material was progressively leaching from the store into the surrounding environment. A subsequent survey of the site conducted eight months later revealed that in response to this survey and remedial actions, the contamination issue once existing on this site had been successfully resolved. Such results highlight the potential of low-altitude unmanned aerial systems to easily and rapidly assess site-wide changes over time – providing highly-visual results; therefore, permitting for prompt remedial actions to be undertaken as required. Use of UAV radiation mapping and airborne photogrammetry to produce a time-resolved assessment of remediation efforts within a Fukushima temporary storage facility.

Commercial graphites are used for a wide range of applications. For example, Gilsocarbon graphite is used within the reactor core of advanced gas-cooled reactors (AGRs, UK) as a moderator. In service, the mechanical properties of the graphite are changed as a result of neutron irradiation induced defects and porosity arising from radiolytic oxidation. In this paper, we discuss measurements undertaken of mechanical properties at the micro-length-scale for virgin and irradiated graphite. These data provide the necessary inputs to an experimentally-informed model that predicts the deformation and fracture properties of Gilsocarbon graphite at the centimetre length-scale, which is commensurate with laboratory test specimen data. The model predictions provide an improved understanding of how the mechanical properties and fracture characteristics of this type of graphite change as a result of exposure to the reactor service environment.

In this work, a low temperature aqueous chemical growth methodology was used for the fabrication of CuO nanostructures. The as-synthesised nanostructures were then elaborately characterised by number of analytical techniques such as scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The obtained nanostructures were observed to possess interlaced rice-shaped structural features with the length and width of individual rice determined to be in the range of 200---300 nm and 50---100 nm respectively. The unique nanostructures when utilised as electrode material exhibited excellent electro-catalytic potential towards oxidation of hydrazine in alkaline media. The excellent conductive of CuO added by the high surface area of obtained nanorice-like structures enabled development of highly sensitive (3087 µA mMź1 cmź2), selective and stable electrochemical sensor for hydrazine. In addition, the successfully application of the developed sensor in spiked tap, bottled and industrial water samples for the detection of hydrazine suggested its feasibility for practical environmental application.

A simple and efficient microwave-assisted procedure for synthesis of L-cysteine-capped nickel nanoparticles (cyst-Ni NPs) in ethylene glycol solvent was demonstrated. The as-synthesised NPs were characterised by ultraviolet–visible (UV–Vis) spectrophotometer, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The cyst-Ni NPs are proved to be excellent heterogeneous catalysts for the 100 % reduction of 4-nitrophenol (4-NPh) in the presence of reductant (NaBH4) within reaction time of 40 s. In contrast, Raney nickel in similar sample environments shows only 25.5 % reduction. The kinetic and energetic behaviours of cyst-Ni NPs were also studied, and the reduction reaction is determined to follow pseudo-first-order kinetics with a rate constant value of 0.115 s−1 and activation energy of 36.1 kJ·mol−1. In addition to its high catalytic competence, cyst-Ni NPs catalyst exhibits excellent recyclability with negligible catalytic poisoning.

This study presents the development of a highly selective and sensitive electrochemical sensor for the determination of melamine from aqueous environments. The sensor system is based on functionalised marigold-like CuO nanostructures fabricated using a controlled hydrothermal process, where the utilised succinic acid is considered to play a dual role as a functionalising and growth controlling agent (modifier). The fabricated nanostructures exhibit sharp and well-ordered structural features with dimensions (thickness) in the range of 10–50 nm. The sensor system exhibits strong linearity within the concentration range of 0.1 × 10−9 to 5.6 × 10−9 M and demonstrates an excellent limit of detection up to 0.1 × 10−10 M. The extreme selectivity and sensing capability of the developed sensor is attributed to the synergy of selective interaction between succinic acid and melamine moieties, and the high surface area of marigold-like CuO nanostructures. In addition to this, the developed sensor was also utilised for the determination of melamine from real milk samples collected from different regions of Hyderabad, Pakistan. The obtained excellent recoveries proved the feasibility of the sensor for real life applications. The sensor system offers an operative measure for detecting extremely low melamine content with high selectivity in food contents.

Uranium encapsulated in grout was exposed to water vapour for extended periods of time. Through synchrotron x-ray powder diffraction and tomography measurements, uranium dioxide was determined the dominant corrosion product over a 50-week time period. The oxide growth rate initiated rapidly, with rates comparable to the U + H2O reaction. Over time, the reaction rate decreased and eventually plateaued to a rate similar to the U + H2O + O2 reaction. This behaviour was not attributed to oxygen ingress, but instead the decreasing permeability of the grout, limiting oxidising species access to the metal surface.

The undertaken study describes synthesis of air resistant copper nanoparticles (Cu NPs) in an aqueous phase using sodium borohydride as a reducing agent via chemical reduction method. The hydrosol has resistant to oxidation by atmospheric oxygen for several days. The air stability was induced by capping Cu NPs with anionic surfactant “sodium dodecyl sulfate (SDS)”. Ascorbic acid was used as an antioxidant. These Cu NPs were characterized by ultraviolet-visible (UV-VIS) spectroscopy, which contributed towards the understanding of surface plasmon resonance (SPR) generation and optical behavior of Cu NPs. It was used as an optical tracer for size control and confirmation of Cu NPs and was found to be affected by various parameters like reaction time, pH, concentration of copper sulfate and the surfactant SDS. SPR peaks were found to shift from 597 to 569 nm, while apparent color changes from yellow to brick red. Further characterization studies were carried out by using fourier transform infrared (FT-IR) spectroscopy to investigate the co-ordination between Cu NPs and SDS. X-ray diffraction (XRD) was used for phase purity of Cu NPs. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used the size and morphological characterization. The average size of the Cu NPs was found to be 15 nm in diameter with an average height of 14 nm. The Cu NPs showed excellent catalytic activity in the reductive degradation of Eosin B (EB) dye in just 16 sec of reaction time and maintained their catalytic activity when reused multiple times. The degradation rate was found to follow first order reaction kinetics with the EB degradation. The Cu NPs enhanced the rate of EB degradation 30 times more than the control test. Copper was found an attractive catalyst in the nanosize regimes. The Cu NPs are more economical as compared to noble metals. The Cu NPs are expected to be suitable alternative and play an imperative role in the fields of catalysis and environmental remediation. Copyright © 2014 VBRI press.

A novel, low energy method for coating different nano-particles via electro-deposition to a recyclable carbon glass supporting structure is demonstrated. In the resulting composite, the nano-material is bound to the substrate surface, thereby removing the potential for causing harmful interactions with the environment. Nano-particles were suspended in a salt solution and deposited at low current densities ( −2 ) producing thin (

A set of thermal barrier coated (TBC) specimens was made from CMSX-4 superalloy containing curved surfaces that are representative of typical turbine blades with a bond coat (BC) of HVOF ‘Amdry 995’ and a top coat (TC) that was air plasma sprayed 7 wt% Y2O3 stabilised ZrO2. The specimens were thermally oxidised at 925 °C for times between 100 and 10,000 h. The residual stresses, both in the TC and the thermally grown oxide (TGO) that formed between the TC and BC upon thermal exposure, were measured on the cross-sections using Raman spectroscopy and photo-stimulated luminescence spectroscopy, respectively. A constraint upon the residual stress in the TC in the vicinity of the interface was found to be due to the growth of TGO. The corresponding microstructural evolution of the TBC and TGO was investigated using scanning electron microscopy to assist understanding of the residual stress distribution within the TC thickness and the undulating TGO. The effect of substrate curvature on the strain levels in the TC was evaluated and considered with respect to the macro-scale failure modes of the coating system.

We have recently undertaken comprehensive computational studies predicting possible crystal structures of the as yet unknown phosphorus carbide as a function of composition. In this work, we report the synthesis of amorphous phosphorus–carbon films by pulsed laser deposition. The local bonding environments of carbon and phosphorus in the synthesised materials have been analysed by x-ray photoelectron spectroscopy; we have found strong evidence for the formation of direct P–C bonding and hence phosphorus carbide. There is a good agreement between the bonding environments found in this phosphorus carbide material and those predicted in the computational work. In particular, the local bonding environments are consistent with those found in the β - InS - like structures that we predict to be low in energy for phosphorus:carbon ratios between 0.25 and 1.

A facile and green seed mediated growth approach for fabrication of well dispersed l -threonine derived nickel nanoparticles (Ni NPs) in an aqueous medium via a modified borohydride reduction method is described. l -Threonine molecules served to organize the nanoscale composites in the form of well dispersed Ni NPs. The basic pH 8.5 was found to favor the formation of spherical and well dispersed Ni NPs as shown in transmission electron microscopy (TEM) micrographs. Freshly prepared Ni NPs possess the nanoscale dimension of 1.68–5.06 nm, as determined from atomic force microscopy (AFM) and TEM data. The Ni NPs thus prepared were used for their catalytic potential in the reduction of congo red (CR) dye selected as a model reagent. The results revealed negligible reduction of dye in the absence of Ni NPs. Conversely the addition of only 0.2 mg Ni NPs produced 100% reduction/degradation efficiency. The used Ni NPs were recovered and reutilized several times for reducing CR without any loss of activity. The current findings are equally extendable for safeguarding the aquatic environment against the pollution caused by other dyes via a facile, highly economical, rapid and efficient reduction/degradation method based on the catalytic potential of Ni NPs.

Understanding the corrosion susceptibility of Magnox alloys during short- and long-term storage in moist air is important. Corrosion of Magnox AL80, Magnox ZR55 and magnesium has been studied in air containing water partial pressures between 200 vppm and ∼80000 vppm, at temperatures of 46 °C–96 °C. Specimens were exposed to air, with and without CO 2 , and argon gas. Metal consumption rates were measured and corrosion products characterised, using optical and scanning electron microscopy, energy dispersive x-ray microanalysis, x-ray diffraction and secondary ion mass spectrometry. Results show the importance of CO 2 gas for suppressing breakaway corrosion in moist air.

This study describes sensitive determination of atropine using glassy carbon electrodes (GCE) modified with Co3O4 nanostructures. The as-synthesised nanostructures were grown using cysteine (CYS), glutathione (GSH) and histidine (HYS) as effective templates under hydrothermal action. The obtained morphologies revealed interesting structural features, including both cavity-based and flower-shaped structures. The as-synthesised morphologies were noted to actively participate in electro-catalysis of atropine (AT) drug where GSH-assisted structures exhibited the best signal response in terms of current density and over-potential value. The study also discusses the influence of functional groups on the signal sensitivity of atropine electro-oxidation. The functionalisation was carried with the amino acids originally used as effective templates for the growth of Co3O4 nanostructures. The highest increment was obtained when GSH was used as the surface functionalising agent. The GSH-functionalised Co3O4-modified electrode was utilised for the electro-chemical sensing of AT in a concentration range of 0.01-0.46 μM. The developed sensor exhibited excellent working linearity (R2 = 0.999) and signal sensitivity up to 0.001 μM of AT. The noted high sensitivity of the sensor is associated with the synergy of superb surface architectures and favourable interaction facilitating the electron transfer kinetics for the electro-catalytic oxidation of AT. Significantly, the developed sensor demonstrated excellent working capability when used for AT detection in human urine samples with strong anti-interference potential against common co-existing species, such as glucose, fructose, cysteine, uric acid, dopamine and ascorbic acid.

The design of biocompatible implants for neuron repair/regeneration ideally requires high cell adhesion as well as good electrical conductivity. Here, we have shown that plasma-treated chitin carbon nanotube composite scaffolds show very good neuron adhesion as well as support of synaptic function of neurons. The addition of carbon nanotubes to a chitin biopolymer improved the electrical conductivity and the assisted oxygen plasma treatment introduced more oxygen species onto the chitin nanotube scaffold surface. Neuron viability experiments showed excellent neuron attachment onto plasma-treated chitin nanotube composite scaffolds. The support of synaptic function was evident on chitin/nanotube composites, as confirmed by PSD-95 staining. The biocompatible and electrically-conducting chitin nanotube composite scaffold prepared in this study can be used for in vitro tissue engineering of neurons and, potentially, as an implantable electrode for stimulation and repair of neurons.

The influence of temperature and time of thermal exposure on the residual stresses developed within a thermal barrier coating (TBC) and the underlying thermally grown oxide (TGO) are investigated. Stress measurements on the TBC and the TGO for specimens with aerofoil geometry features were made at positions of fixed curvature using Raman spectroscopy and photo-stimulated piezoluminescence spectroscopy. The Raman shifts were converted to stress via a factor measured using a diamond anvil cell (DAC). The acquired stresses were shown to be tensile at all positions measured in the as-coated specimens, and change progressively from tensile to compressive with thermal exposure. Residual stresses within the TGO were found to be a function of the ageing temperature and time, substrate geometry and thickness of the TBC. The results are discussed with respect to the long term integrity of the coatings.

The study reports mechanical performance of the recycled glass fibres produced from a water-based solvolysis technology, known as the hydrolysis process. The chemical reaction was carried out using sub-critical water to dissolve polyester resin and recover the glass fibres from composites. The effect of temperatures, times, catalyst and water amount on mechanical properties of the recovered glass fibres were investigated. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and time-of flight secondary ion mass spectroscopy (ToF-SIMS) analyses were also employed to examine the fibre surface associated with the polyester resin eliminated level after the hydrolysis reaction. The results revealed that by carefully adjusting the hydrolysis parameters the tensile strength and failure strain of the recycled fibres decrease by approximately 40–70% in comparison with virgin fibres while Young’s moduli remain similar. The relationship between the hydrolysis conditions, recovered fibres and mechanical performance was discussed in this study.

In this paper, we explored the relationship between thermal aging and the residual stresses developed within a thermal barrier coating (TBC) and the underlying thermally grown oxide (TGO). Superalloy model specimens (CMSX4) with a curved geometry designed to simulate key features of turbine blades coated with air plasma sprayed (APS) 7 wt.% Y2O3-stabilised ZrO2 applied to an Amdry 995 bond coat were oxidised in the temperature range 900°C to 975°C for various lengths of time. Stress measurements on both the TBC and the underlying TGO were made at positions of known curvature using Raman and photo-stimulated piezo-luminescence spectroscopy (PLPS). The residual stress values reflect the interaction between TGO and TBC, which has the potential to be used as an indicator of service lifetime. The results are discussed with respect to the origin of the stress changes and the long term integrity of the coating.

Iron nanoparticles were produced using extracts of green tea leaves (GT-Fe NPs). The materials were characterized using TEM, SEM/EDX, XPS, XRD, and FTIR techniques and were shown to contain mainly iron oxide and iron oxohydroxide. The obtained nanoparticles were then utilized as a Fenton-like catalyst for decolorization of aqueous solutions containing methylene blue (MB) and methyl orange (MO) dyes. The related experiments investigated the removal kinetics and the effect of concentration for both MB and MO. The concentrations of dyes in aqueous solution were monitored using ultraviolet–visible (UV–vis) spectroscopy. The results indicated fast removal of the dyes with the kinetic data of MB following a second order removal rate, while those of MO were closer to a first order removal rate. The loading experiments indicated almost complete removal of both dyes from water over a wide range of concentration, 10–200 mg L−1. Compared with iron nanoparticles produced by borohydride reduction, GT-Fe nanoparticles demonstrated more effective capability as a Fenton-like catalyst, both in terms of kinetics and percentage removal., Birzeit University

Nanosized zero-valent iron (nZVI) is increasingly gaining interest as an efficient sorbent for various types of aqueous pollutants. In this study, nZVI was synthesised by the borohydride reduction method, characterised and then examined for the removal of aqueous Co 2+ ions over a wide range of concentrations, from 1 to 1000 mg/L. The size of nZVI particles was predominantly within the range of 20–80 nm, and only limited oxidation was observed in samples aged for a period of 2 months. The experiments investigated the effects of V / m ratio, concentration, contact time, repetitive loading, pH and aging on the extent of retardation of Co 2+ ions. Iron nanoparticles demonstrated very rapid uptake and large capacity for the removal of Co 2+ ions. Effective uptake was observed even after a number of repetitive trials. The extent of Co 2+ uptake increased with the increasing pH. X-ray photoelectron spectroscopy (XPS) indicate that the fixation of Co 2+ ions takes place through the interaction of these ions with the oxohydroxyl groups on the iron nanoparticle surfaces in addition to spontaneous precipitate formation at high loadings.

In this study, nZVI prepared by borohydride reduction was applied for the removal of Cu2+ ions under a variety of experimental conditions. The uptake experiments investigated the effects of initial...

Laboratory experiments with two cyanobacterial strains grown on low-nutrient agar media in the presence of biotite flakes were performed in order to reveal possible mechanisms and rates of cyanobacterial bioweathering. Both cyanobacteria colonized the biotite flakes. Leptolyngbya grew mostly in the biotite interlayers, whereas Hassallia colonized the sides and the topmost surface of the biotite flakes. After a 3-month incubation, rounded features including cyanobacterium-shaped pits were observed on the biotite surface cleared of the organic material. No such features were observed on flakes incubated for 1 month.

Atomic force microscopy (AFM) has been used to monitor the appearance and behaviour of the hormone progesterone on mineral surfaces, including mica and highly oriented pyrolytic graphite (HOPG). Different solvents have been used resulting in various features on the two substrates. After the application of 254 nm ultra-violet (UV) light, changes in structure of the adsorbed hormone have been observed. To understand the reactions at the progesterone-mica interface in aqueous solution, adsorption has been studied in situ with AFM.

Enhancing vitamin D-induced human osteoblast (hOB) maturation at bone biomaterial surfaces is likely to improve prosthesis integration with resultant reductions in the need for revision arthroplasty consequent to aseptic loosening. Biomaterials that are less appealing to microorganisms implicated in implant failures through infection are also highly desirable. However, finding surfaces that enhance hOB maturation to active vitamin D yet deter bacteria remain elusive. In addressing this, we have sought to bio-functionalise titanium (Ti) with lysophosphatidic acid (LPA) and related, phosphatase-resistant, LPA analogues. The impetus for this follows our discovery that LPA co-operates with active vitamin D3 metabolites to secure hOB maturation in vitro including cells grown upon Ti. LPA has also been found, by others, to inhibit virulence factor production and biofilm formation of the human opportunistic pathogen Pseudomonas aeruginosa. Collectively, selected LPA species might offer potential dual-action surface finishes for contemporary bone biomaterials. In attaching a phosphatase-resistant LPA analogue to Ti we took advantage of the affinity of alkane phosphonic acids for TiO2. Herein, we provide evidence for the facile development of a dual-action Ti surface for potential orthopaedic and dental applications. Successful conjugation of an LPA analogue (3S)1-fluoro-3-hydroxy-4-(oleoyloxy)butyl-1-phosphonate (FHBP) to the Ti surface was supported through physiochemical characterisation using x-ray photoelectron spectroscopy and secondary ion mass spectrometry. hOB maturation to active vitamin D3 was enhanced for cells grown on FHBP-Ti whilst these same surfaces exhibited clear antiadherent properties towards a clinical isolate of Staphylococcus aureus.